package oop.part8.java2;
/**
 * 单例模式的懒汉式实现
 *
 */
public class SingletonTest2 {
  public static void main(String[] args) {

    Order order1 = Order.getInstance();
    Order order2 = Order.getInstance();

    System.out.println(order1 == order2);
  }
}


class Order{

  // 1.私有化类的构造器
  private Order() {}

  // 2.声明当前类对象，没有初始化
  // 4.此对象也必须声明为static的
  private static Order instance = null;

  // 3.声明public、static的返回当前类对象的方法
  public static Order getInstance() {

    if (instance == null) {

      instance = new Order();
    }
    return instance;
  }
}